Vacuum control drive

ABSTRACT

A two-stage vacuum control drive is disclosed in which a vacuum control drive, consisting of a roll membrane movably mounted to counteract the action of a spring under the influence of a vacuum, is mounted displaceably in the housing of a second similar vacuum control drive. The two drives are controlled independently and have a cumulative effect on the total travel of the device.

United States Patentv [191 Hahn 1 July 23, 1974 VACUUM CONTROL DRIVE3,090,359 5/1963 Hoppenstand 92/64 x Inventor: Johann Hahn, StuttgartGermany 3,683,753 8/1972 Johnson M 92/48 [73] Assignee: SuddeutscheKuhlerfabrik Julius Fr.

Behr, Stuttgart, Germany Primary Examiner-Edgar W. Geoghegan AssistantExaminerAbraham Hershkovitz [22] Flled: 1972 Attorney, Agent, orFirm-Browdy & Neimark [21] Appl. No.: 308,462

[30] Foreign Application Priority Data 57 TR T Nov. 26, 1971 Germany2158786 A two-stage vacuum control drive is disclosed in Cl r which avacuum control drive, consisting of a roll 9 membrane movably mounted tocounteract the action [51] Int. Cl. FOlb 19/00 of a spring under theinfluence of a vacuum, is [58] Fle d of Sea ch 92/ mounted displaceablyin the housing of a second simi- 167 lar vacuum control drive. The twodrives are controlled independently and have a cumulative effect on [56]References Cited the total travel of the device.

UNITED STATES PATENTS 3,081,134 3/1963 14 Claims, 2 Drawing FiguresMasser 91/167 X PATENTEDJULZMQN 3,824,903

SHEU 2 [IF 2 l VACUUM CONTROL DRIVE FIELD OF THE INVENTION The inventionconcerns a vacuum control drive, especially for automatic ormanualremote control in motor vehicles, as for example automatic control ofheater circuits, with vacuum control units in which a spring-loaded rollmembrane or the like is displaceable under the influence of a vacuum ina housing.

BACKGROUND OF THE INVENTION Vacuum control drives, in which a rollmembrane is movably mounted to counteract the action of a spring underthe influence of a vacuum in the usually bipartite sometimes cylindricalhousing, are known.

The corresponding control elements are therefore movable, especiallydisplaceable, within a certain range, which corresponds roughly to thetravel of the roll membrane.

It is also known to connect two or more vacuum sources to the control,or, in order to increase'the effective travel to use two essentiallyidentical vacuum control drives of the above-described type and to 'linthem by a suitable coupling.

The expenditure of labor required to make and assemble these'prior artdouble control drives is very great, however.

Hence, the object of the invention is to make a twostage vacuum controldrive that is simple to make and assemble and in particular requiresonly a small amount of space. 7

SUMMARY OF THE INVENTION This goal is achieved according to theinvention primarily by the fact that in a vacuum control drive of thetype described above, a first vacuum control drive in a housing ismounted displaceably in the housing of a second vacuum control drive.

Thus, it is advantageously brought about that the two vacuum controldrives are each operated and controlled independently of each other froma connected vacuum source, and the resultant travel is the total effectof the two active vacuums.

It is especially advantageous if a retaining section is mounteddisplaceably in an intermediate section, said retaining sectionbeingconnected .to an upper part of the housing holding one edge of theroll membrane, while a lower part of the housing holding a second rollmembrane is connected to the intermediate section. This arrangementallows an advantageous telescopelike displaceability of one vacuumcontrol drive stage relative to the other.

According to a first sample embodiment of the invention, a connectingstub is provided in the housing of the retaining section for connectionof the vacuum to the upper control drive and a longitudinal slot isprovided in the intermediate section as a passageway and guide for theconnecting stub.

The longitudinal slot thus serves advantageously simultaneously as anupper stop and as a guide for the upper control drive in the housing ofthe lower vacuum drive.

Advantageously, fastening means are provided in the lower part of thehousing to connect the control drive with other structural elements.

The lower part of the housing of the lower vacuum control drive has apreferably central connecting stub for the vacuum connection and a torusas a support for a membrane counter spring.

According to a further feature of the invention, it is especiallyadvantageous if the lower part of the housing and floor section of theretaining section each have a circular stop as a stroke limiting devicefor the roll sleeves, which interact with the preferably vulcanized stopplates mounted in the upper parts of the roll sleeves.

An embodiment that is structurally especially advantageous is obtainedif the retaining section and lower housing section each have a bead thatfits into the upper part of the housing and/or the intermediate sec tionand ensures a tight seal by means of elastic clamping elements. Thetight seal may further be ensured by rolling, caulking or spraying.

According toa second sample embodiment of the invention, the lower partof thehousing has two vacuum connection openings, one of which isconnected to the upper control drive by a flexible connection.

It is especially advantageous if a rubber or plastic tube is used as theconnection, said tube being connected to a preferably'centrally locatedopening in the stop plate of the lower roll membrane and simultaneouslyto the floor of the retaining section.

As stops, it is advantageous to use circular disks in a groove in thefloor of the retaining section and in a flange on the lower part of thehousing.

According to an improvement of the invention, the spring tension of thespring in the lower stage is set different from the spring tension ofthe spring in the upper stage. It is especially advantageous if thetension of the lower spring is greater than the tension of the upperspring in the compressed state.

In a second improvement it is especially advantageous if the fasteningmeans is mounted laterally on the housing.

BRIEF DESCRIPTION OF THE DRAWINGS Further advantages and features of theinvention will be described in the reference to the drawing, which showstwo sample embodiments in schematic form:

FIG. 1: A side elevation partly in section showing a first sampleembodiment with a side connection for the upper control drive, and

FIG. 2: A side elevation partly in section showing a second sampleembodiment of the invention with essentially parallel connecting stubsfor the vacuum connections of both control drives.

DESCRIPTION OF PREFERRED EMBODIMENTS FIG. 1 shows a first sampleembodiment of the invention with the left half in cross section and theright half in outside view and turned through approximately Thetwo-stage vacuum control drive according to the invention consists of aretaining section 1 with an upper part 2, an intermediate section 3 anda lower housing section 4. Retaining section 1 and upper housing section2 in the floor 20 of retaining section 1 form the housing for the firststage I of the vacuum control drive. An intermediate section 3 withlower housing section 4, on the other hand, together with the floor 20of re taining section 1, form the housing for the second, lower stage IIof the two-stage vacuum control drive according to the invention. Theupper first stage I has a connecting stub 5, mounted somewhat radiallyand laterally in the lower part-of retaining section 1. lnterme- 3 diatesection 3 has a slot 14 in which the connecting stub is displaceable ina concentric manner. Slot 14 serves to guide connecting stub 5, whilethe upper end of slot 14 serves as a stop for retaining-section 1 incooperation with connecting stub 5.

Between a circular flange of the retaining section 1 and a circularhousing 26 of the upper housing section 2, the edge of an upper rollmembrane is clamped with interposition of an upper sealing ring 8.Elastic fastening clamps l2 serve to ensure a tight seal. The tight sealmay further be ensured by rolling, caulking or spraying. This rollmembrane is pressed upward against an upper spring 17 that rests onfloor of retaining section 1 against a circular stop 19, as shown in thedrawing. The upper seal consists of an upper end plate 24, connected insuitable fashion to a control element 28. The floor 20 of retainingsection 1 has a circular bearing surface that serves as the stop for themovement of the upper roll membrane 15 and/or the upper end plate 24.

In the lower housing section 4 a connectingstub 6 is provided for thevacuum to the lower vacuum control drive stage II. In addition,fastening means 7' and 7" can be formed on it.

The intermediate section 3 is again clamped in an annular flange on thelower housing section 4 with a circular housing 27, with interpositionof a lower sealing ring 9. Elastic fastening clamps 12 serve for a tightconnectiomThe tight seal may further be ensured by rolling, caulking orspraying. Further, a stop-ring-plate 13 is provided between the annularflange 11 and the circular housing 27. A lower roll membrane 16 ispressed upward on the one hand by spring 18 which bears against a lowercircular stop 21 on the lower housing section 4 (in the drawing), and isclamped with its edge between the annular flange l1 and the circularhousing. In the upper part of the roll membrane 16 a lower end plate 25is provided, preferably vulcanized. This end plate interacts with acircular lower bearing 23 in the lower housing section 4.

A two-stage vacuum control drive according to the invention and in'thesample embodiment in FIG. 1

works as follows:

The vacuum connections 5 and 6 are connected in the appropriatecorresponding vacuum sources. If for example the upper stage I isevacuated first, roll membrane 15 is pulled downwards against the actionof a spring 17. The travel is determined only by the distance betweenthe edge of the upper circular stop 22 and the upper housing section 2.In a control drive that was constructed, this travel was 26 mm.

Regardless of the vacuum in stage I, a vacuum can be created in thelower stage II via the connecting stub 6. Then the lower roll membrane16 is displaced downward against the action of spring 18. In thismovement, the lower roll membrane 16 carries down along with it thefloor of retaining section I, linked and/or vulcanized together with thelower end plate 25. The result is a telescopic displacement of retainingsection 1 inside intermediate section 3. The connecting stub 5 for thevacuum connection to upper stage I participates in the movement. Thetravel is limited on the one hand by the distance of the floor 20 fromthe upper surface of the lower circular bearing 23, as shownschematically in the drawing. On the other side of the upward travel islimited by the upper edge of slot 14. It is immaterial for the manner ofaction of the control drive whether first the upper stage I and then thelower stage II are controlled by the vacuum or vice versa. In fact, thepossibility exists to evacuate both stages simultaneously.

Thus, when a vacuum is applied to connection 5 in the sample embodimentaccording to FIG. 1, mem- If a vacuum is applied to both connection 5and connection 6, membrane 15 is displaced in upper stage I because ofthe vacuum applied to connection 5 and remains in the same position withrespect to housing sections 1 and 2, even when the vacuum applied toconnection 6 displaces housing 1, 2 with 20 downward as a unit.

It'is especially advantageous if the spring tension or spring l8 if thelower stage ismade greater than the spring tension of spring 17 of theupper stage I in the compressed state. In the constructed sampledescribed above the travel of the lower stage was 14 mm, so that thetotal travel was approximately 40 mm.

Each stage is sealed off by the clamped and/or vulcanized roll membranes15 and 16. It is possible to use identical roll membranes in bothstages, but with different amounts of travel. 7

Retaining section 1 with upper housing section 2, as mentioned above, isconnected to lower roll membrane 16 via floor 20. With a total travel ofapproximately 40 mm the constructed example only has an overall heightof 75 mm.

FIG. 2 shows a modified sample embodiment in which the vacuum connectionfor the upper stage I is no longer located laterally but in the floor ofthe control drive. I I

The construction of the control drive according to the sample embodimentin FIG. 2 essentially corresponds to the construction according to thesample embodiment in FIG. 1. A retaining section 31 is provided with anannular flange 40 and tightly sealed to the upper housing section 32with interposition of an upper sealing ring 38. A roll membrane 45 is'tightly clamped between the annular flange 40 and a circular housing 58on the upper housing section 32. Th roll membrane 45 is pressed upwardby a spring 47, which bears on an upper annular notch 49 in bottom 50 ofretaining section 31 (in the drawing). It has an upper connecting plate54. The travel is mainly limited by a circular upper bearing 52 in thefloor 50 of holder 31. Annular flange 40 and upper circular housing 58may be provided with notches 42 for fastening clamps (not shown),similar to the elastic fastening clamps 12 in FIG. 1, said notches beingarranged at intervals around the edge. The connection between the lowerannular flange 41 of a floor 34 and a lower circular housing 59 of anintermediate section 33 is achieved in similar fashion. Intermediatesection 33 is closed off by a lower tion of a lower sealing ring 39 anda strike-ring-plate 43. This lower roll membrane 46 is pressed upward bya lower spring 48 that bears on a circular lower bearing 53 (in thedrawing). In the upper area of the lower roll membrane 46 a lower endplate 55 is provided, preferably vulcanized. The lower end plate 55 hasa connecting opening 60 (preferably central) for the vacuum. An elasticconnection 56 made of rubber or plastic is connected to this connection60, the other end of said elastic connection being connected toconnecting stub 35 for stage I.

A lower torus 51 serves as a bearing for the lower end plate 55 of thelowerroll membrane 46. The upper bearing is an end plate 44 connected toretaining sec tion 31. This upper end plate 44 interacts with the lowerend circular bearing plate 53.

The floor 50 of retaining section 31 is firmly connected to the lowerroll membrane 46 and/or the lower end plate 55 by a connecting piece 56.

Fastening means not shown in detail may be inserted, screwed or fastenedin another suitable fashion to connectors 37.

The manner of operation of the sample embodiment according to FIG.2'essentially corresponds completely to the manner of operation of thesample embodiment according to FIG. 1. The sole difference is that theplacement of the connection for the vacuum to the upper stage I isshifted from the outer wall to the total housing, so that no externalmovable connections are required.

The invention is not limited to the sample embodiment shown anddescribed. It includes as well all modifications by experts in the fieldand partial as well as subcominations.

1. In a vacuum control drive including a housing,'a spring-loaded rollmembrane displaceably mounted in said housing for displacement under theaction of a vacuum and a connection means for connecting the drive to asource of vacuum, the improvement wherein:

the drive comprises two stages, the

prising a first housing,

a first spring-loaded roll membrane displaceably mounted in said firsthousing for displacement under the action of a vacuum, and

a first connection means for connecting said first stage to a source ofvacuum,

said first'housing comprising a retaining section and an upper housingsection connected thereto, said first roll membrane being connected tosaid first housing between said retaining section and said upper housingsection; and

the second stage comprising a second housing,

a second spring-loaded roll membrane displaceably mounted in said secondhousing for displacement under the action of a vacuum, and

a second connection means for connecting said second stage to a sourceof vacuum,

said second housing comprising an intermediate section and a lowerhousing section connected thereto, said second roll membrane beingconnected to said second housing between said intermediate section andsaid lower housing section;

first stage comwherein said retaining section is displaceably mounted insaid intermediate section such that said first housing and said firstroll membrane of said first stage are displaceably mounted with saidsecond housing for displacement in conjunction with the displacement ofthe second roll membrane.

2. Control drive according to claim 1, wherein said first connectingmeans comprises a connecting stub connected to said retaining sectionand said intermediate section includes a lengthwise slot acting as apassageway and guide for said connecting stub.

3. Control drive according to claim 1, further including fastening meansin said lower housing section.

4. Control drive according to claim 1 wherein said retaining section andsaid lower housing section each have a flange that is overlappedrespectively by said upper housing section and said intermediate sectionand further wherein said first and second stages each further include anelastic clamping means for ensuring a tight seal at said overlappedflanges.

5. Control drive according to claim 4 wherein the tight seals arefurther ensured by rolling, caulking, or spraying.

6. Control drive according to claim 1, further including laterallyaffixed fastening means on the housing.

7. A control drive in accordance with claim 1 wherein said secondspring-loaded roll membrane comprises a second roll membrane and asecond counter spring, wherein said lower housing section includes atorus as a supporting bearing for said second counter spring, andwherein said second connecting means comprises a central connecting stubconnected to said lower housing section.

8. A control drive in accordance with claim 1 wherein said first springloaded roll membrane further includes a first end plate connected to theportion of said first roll membrane opposite that portion thereofconnected to said first housing, wherein said second spring loaded rollmembrane further includes a second end plate connected to the portion ofsaid second roll membrane opposite that portion thereof connected tosaid second housing, wherein said retaining section includes a firstcircular bearing menus for limiting the travel of said first end plate,and wherein said lower housing section includes a second circularbearing means for limiting the travel of said second end plate.

9. A control drive in accordance with claim 8 wherein said first andsecond end plates are vulcanized.

10. A control drive in accordance with claim 1 wherein said first andsecond connection means respectively comprise first and secondconnecting stubs, both connected to said lower housing section, saidfirst connection means further including an elastic connection betweensaid retaining section and said first connecting stub.

11. Control drive according to claim 10, wherein circular bearing platemeans for stopping the travel of said second roll membrane are mountedin a groove within the bottom of said retaining section and on a flangeon the lower housing section.

12. A control drive in accordance with claim 10 wherein said secondspring-loaded roll membrane further includes a second end plateconnected to the portion of said second roll membrane opposite thatportion 8 spring and wherein said two counter springs are setdifferently.

14. Control drive according to claim 13, wherein the spring tension ofthe counter spring in said second stage is set greater than the springtension of the counter spring in said first stage in the compressedstate.

1. In a vacuum control drive including a housing, a springloaded roll membrane displaceably mounted in said housing for displacement under the action of a vacuum and a connection means for connecting the drive to a source of vacuum, the improvement wherein: the drive comprisEs two stages, the first stage comprising a first housing, a first spring-loaded roll membrane displaceably mounted in said first housing for displacement under the action of a vacuum, and a first connection means for connecting said first stage to a source of vacuum, said first housing comprising a retaining section and an upper housing section connected thereto, said first roll membrane being connected to said first housing between said retaining section and said upper housing section; and the second stage comprising a second housing, a second spring-loaded roll membrane displaceably mounted in said second housing for displacement under the action of a vacuum, and a second connection means for connecting said second stage to a source of vacuum, said second housing comprising an intermediate section and a lower housing section connected thereto, said second roll membrane being connected to said second housing between said intermediate section and said lower housing section; wherein said retaining section is displaceably mounted in said intermediate section such that said first housing and said first roll membrane of said first stage are displaceably mounted with said second housing for displacement in conjunction with the displacement of the second roll membrane.
 2. Control drive according to claim 1, wherein said first connecting means comprises a connecting stub connected to said retaining section and said intermediate section includes a lengthwise slot acting as a passageway and guide for said connecting stub.
 3. Control drive according to claim 1, further including fastening means in said lower housing section.
 4. Control drive according to claim 1 wherein said retaining section and said lower housing section each have a flange that is overlapped respectively by said upper housing section and said intermediate section and further wherein said first and second stages each further include an elastic clamping means for ensuring a tight seal at said overlapped flanges.
 5. Control drive according to claim 4 wherein the tight seals are further ensured by rolling, caulking, or spraying.
 6. Control drive according to claim 1, further including laterally affixed fastening means on the housing.
 7. A control drive in accordance with claim 1 wherein said second spring-loaded roll membrane comprises a second roll membrane and a second counter spring, wherein said lower housing section includes a torus as a supporting bearing for said second counter spring, and wherein said second connecting means comprises a central connecting stub connected to said lower housing section.
 8. A control drive in accordance with claim 1 wherein said first spring loaded roll membrane further includes a first end plate connected to the portion of said first roll membrane opposite that portion thereof connected to said first housing, wherein said second spring loaded roll membrane further includes a second end plate connected to the portion of said second roll membrane opposite that portion thereof connected to said second housing, wherein said retaining section includes a first circular bearing menns for limiting the travel of said first end plate, and wherein said lower housing section includes a second circular bearing means for limiting the travel of said second end plate.
 9. A control drive in accordance with claim 8 wherein said first and second end plates are vulcanized.
 10. A control drive in accordance with claim 1 wherein said first and second connection means respectively comprise first and second connecting stubs, both connected to said lower housing section, said first connection means further including an elastic connection between said retaining section and said first connecting stub.
 11. Control drive according to claim 10, wherein circular bearing plate means for stopping the travel of said second roll membrane are mounted in a groove within the bottom of said retaining sectiOn and on a flange on the lower housing section.
 12. A control drive in accordance with claim 10 wherein said second spring-loaded roll membrane further includes a second end plate connected to the portion of said second roll membrane opposite that portion thereof connected to said second housing, said second end plate having a hole therein and wherein said elastic connection comprises a rubber or plastic tube, said tube passing through and connecting with said hole in said second end plate.
 13. A control device in accordance with claim 10 wherein said first and second spring-loaded roll membranes each comprise a roll membrane and a counter-spring and wherein said two counter springs are set differently.
 14. Control drive according to claim 13, wherein the spring tension of the counter spring in said second stage is set greater than the spring tension of the counter spring in said first stage in the compressed state. 